The present invention relates to a fuel injection apparatus for an internal combustion engine and, more particularly, to a fuel injection apparatus having a means for diverting part of the fuel to an accumulator chamber when the fuel is compressed and supplied.
In conventional fuel injection apparatuses, the fuel is compressed and supplied by a plunger and is then injected from an injection nozzle. In this simple construction, a proper injection rate of a cylinder injection type diesel engine varies in accordance with the engine speed, the engine load, and the engine temperature. Thus, a single fuel injection apparatus can hardly provide an optimum injection rate for the diesel engine of the type described above.
It is therefore desired that a practical apparatus be developed which is capable of controlling the injection rate in accordance with the operating conditions.
A method has been proposed wherein the injection rate is relatively easily changed by constantly accumulating part of the fuel when the fuel is compressed and supplied. However, this conventional method has a disadvantage in that the accumulated amount cannot be arbitrarily controlled due to the high pressure of the fuel. When the accumulated amount of fuel to be injected is optimally set at the time of idling, the accumulated amount of fuel is thus determined at the set level throughout the entire range of the engine speed. For this reason, optimum accumulation characteristics cannot be obtained throughout the above range. As a result, effective combustion cannot be obtained.